TOP-LEVEL DOMAINS

As of 2015, IANA (Internet Assigned Numbers Authority) distinguishes the following groups of top-level domains:

Infrastructure top-level domain (ARPA): This group consists of one domain, the Address and Routing Parameter Area. It is managed by IANA on behalf of the Internet Engineering Task Force for various purposes specified in the Request for Comments publications.

Generic top-level domains (gTLD): Top-level domains with three or more characters
restricted generic top-level domains (grTLD): These domains are managed under official ICANN accredited registrars.

Sponsored top-level domains (sTLD): These domains are proposed and sponsored by private agencies or organizations that establish and enforce rules restricting the eligibility to use the TLD. Use is based on community theme concepts; these domains are managed under official ICANN accredited registrars.

Country-code top-level domains (ccTLD): Two-letter domains established for countries or territories. With some historical exceptions, the code for any territory is the same as its two-letter ISO 3166 code.